


This Earth is a Funhouse Mirror

by JoeMcJoe



Category: Supergirl (TV 2015), The Flash (TV 2014)
Genre: Comic universes are complicated!, Gen
Language: English
Status: Completed
Published: 2016-05-10
Updated: 2016-06-14
Packaged: 2018-06-07 14:37:26
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 7
Words: 11,087
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6809254
Author URL: https://archiveofourown.org/users/JoeMcJoe/pseuds/JoeMcJoe
Summary: <blockquote class="userstuff">
              <p>Kara loses her powers and ends up on Barry's earth, so the only one who can help them against the intergalactic bad guys is her counterpart on this earth.</p>
            </blockquote>





	1. A World She Never Made

Kara Danvers was flying. As Supergirl, she had been taking the long way home lately, trying to get to the bottom of a series of disappearances, but there had been nothing. She had taken to thinking to herself as she flew above the city. Today she was wondering about J’onn J’onzz. _How many powers does J'onn have? He changes shape, can fly—_

A knot of black-clad armed men huddled on the roof of a skyscraper. _That can't be good_ , she thought. Winn hadn’t said anything about a police exercise. She spoke, trusting to the DEO to catch her words. "I've got bad guys on Binder, near E and O Avenues. I see six but haven’t used X-rays. Can you call the police? Someone will have to pick them up."

She lit softly on the roof. "Is this like a fraternity thing?" she asked them. "Because you’re a little far from campus."

She caught the first wired dart. "Tasers? Really?" A half dozen more fastened onto her with a series of _chuff_ sounds. "It doesn’t matter how many you use—"

"Now," barked one man.

The chambers slung under the bullpups glowed purple and she felt a wave of weakness. _Not electricity._ She pulled on one of the wires and the gun flew toward her. It _hurt_ as it bounced off her. She hit one man and he barely fell over. The weakness grew stronger as she hit a second. He doubled over but that was all.

"Losing powers," she said so that the DEO knew. "Not a solar flare."

"Superg—" said Vasquez in her ear, but by then the men were swarming over her. Everything went black.

* * *

Barry Allen was running. By making his body race, his thoughts couldn’t. "Come on, Cisco," he said. "Find me something. Anything. A cat in a tree."

"I have weird lights."

"Weird lights are good."

Cisco gave him the address. "Residential neighbourhood. Might just be a party out of hand."

"On a Tuesday?"

"If I partied it might be on a Tuesday."

Barry grinned. "If you partied on a Tuesday, I’d know I was on a different Earth."

The lights did in fact look weird: unnatural lozenges of light in pastel shades, leaking out from behind the shades of the condo. It sounded like a brawl inside, not a party. Barry raced up the side of the condominium as a woman was thrown through the window. Barry grabbed her and carried her down to the ground.

He took a look at her to check if she needed medical care. Blonde, young, already heavily bruised, probably pretty before the fight. She looked familiar.

"Kara?" he said. But Kara didn’t bruise, and this woman was wearing a tan jumpsuit, not the Supergirl outfit. Maybe this was her Earth-One doppelgänger?

"Barry," she said. "Thank goodness. Lost my powers, so--"

His first priority was to get her safe. He could spare ten minutes to get her to safety.

When Cisco finished extinguishing her flaming jumpsuit, Barry said, "Great to see you, but what's going on?"

"I wish I knew," she said. "One minute I'm in National City, facing men in masks, the next I'm in a cell, on your earth, and I have no powers."

Cisco said to Barry, "I called Caitlin to come in and look at those bruises." He handed her a sweatsuit. "I'm Cisco. I guessed at the size, but we have like three dozen pair of the pants. They were never as popular as the tops."

"He's safe," said Barry. "He's one of my best friends. He’s kinda like my Winn."

 "Miss, I am made of win." Cisco looked at the two of them. "Which is not what you meant."

"Kara Danvers," she muttered through swollen lips. "Winn is my friend. Whoa. Still dizzy. I hate being vulnerable."

"Hey. We'll get you home. These guys clearly have dimension-spanning tech."

"And they took my powers. Maybe they can take yours."

"I'll be careful," said Barry. He was gone.

"Do you want something to eat?" asked Cisco as he seated himself behind the console. "We keep our pantry full because, Barry."

Kara brightened. "Do you have doughnuts?"

* * *

The window was now intact. Barry scouted the floors and saw that there was no debris on the ground.   "Cisco: Give me the address again.  Looks like nothing happened here."

"GPS shows you’re in the right place, dude."

"Barry? Be a CSI, not a superhero," said Kara.

"Right." Barry slowed down to examine the scene.

The paint on the window frame was wet.  What kind of planning did it take to have the window replaced in ten minutes? Or maybe superspeed? Most of the obvious debris was gone from the ground.

He scouted the building and then returned to STAR Labs.

* * *

Caitlin was dabbing medicinal things on Kara’s bruises and split lip.

Barry said, "It was clearly a prison, and they had some kind of heavy equipment that they moved out in ten minutes. The prison bedrooms were wired with something that had been removed. The big debris was gone from the yard but some of the glass wasn’t."

"How many were there?" Caitlin asked Kara.

"On the roof, the first time I saw them, more than six. I didn’t look for extras. Six or sixty doesn’t normally matter to me. In the condo, I broke free at bathroom break. There were maybe nine men, though I fought only three." She shrugged and then winced as Caitlin touched her lip. "My sister has been teaching me fighting."

"Did they have superpowers? Like speed? If they're crossing dimensions and stealing powers…"

"Well… One was grabbing these handles, some kind of machine, there was a light show, and then he let go to punch me. I went through the window. I don’t think he was expecting that. Glad you caught me, Barry." She tried to smile. "It’s getting to be a habit."

"I’m just glad I was there to help. I can take you home, with Cisco's help."

"Look, I fought that guy before, on the roof, and he wasn’t anywhere near that strong. No: He had my powers. I’m going to get them back."

"If he’s as strong as you are, we need help," said Barry.

Cisco said, "Green Arrow and his crew aren’t going to be a help. They’re smart, but this kind of metahuman isn’t really their bag."

Barry said, "And Firestorm is in another time." At Kara’s look, he said, "Complicated. No, I was thinking of something a bit different."

"Go on."

"After we met, I wanted to see if there was a duplicate of you on this earth, because there was no duplicate of STAR labs or Cisco or Caitlin or Dr Wells on your earth."

"You looked for me? How sweet." She smiled that thousand-watt smile.

"I found the Earth One version of you." He paused. "Kara, I'm sorry. She died with her family, when she was fourteen. "

"Alex and Eliza are dead?"

"They weren't your Alex and Eliza," said Barry gently. "There was an accident at the lab."

"You said the Danvers? Why was she even with them? There's no Superman here, no one to take her to the Danvers. Maybe this Kara got here first and Kal got stuck in the Phantom Zone."

"Maybe. Sure."

"Multiverse," agreed Caitlin. "Anything can and did happen."

"She's not dead. She went into hiding," said Kara. "She faked her death. There is nothing on this planet that would easily kill someone from Krypton."

"Really? You guys named yourself after an inert gas?" said Cisco as he sat down at his console. "You married to that?"

"We can check non-intrustively," said Caitlin. "Kara, even without your powers, you’re demonstrably non-human."

"I look human. Most of the aliens we've dealt can pass."

"Right, you pass," Caitlin said. "Convergent evolution, I suppose. Your blood is red, and your general morphology is correct. But your lungs have an extra lobe, your heart's in the wrong place, your spleen isn't your spleen plus it shares space with another organ, and your mitochondria aren't mitochondria." Caitlin turned to Cisco. "At the very least, Kara absorbs sunlight in a way that humans don't, so satellites might pick her up."

"You want me to find one person who might have gone into hiding ten years ago. Because she absorbs some light. Sheesh."

"You might not be as fast as Felicity, but you're just as good," said Barry.

Cisco got a far-away look on his face. "Can't use mass or temperature..."

"We have some time," Barry told Kara. "Coffee?"

* * *

Jitters was nearly empty. A half-dozen empty plates sat on the table. Barry and Kara sat away from the plaque commemorating the slain police officers.

"With Cisco, it's movie dialogue instead of song lyrics," laughed Barry.

"Hey, Barry. Who's your friend?" Iris smiled while not obviously looking Kara up and down. Kara looked self-conscious about the sweats.

"Iris! Kara, Iris, Iris, Kara. Kara and I met a while ago on a case. She doesn’t normally dress this way, but there was an…accident."

"A significant flashy kind of case?" asked Iris.

"Pretty much," admitted Barry. "And the same kind of accident."

"Say no more," said Iris.

"She knows?" Iris and Barry both nodded. "I’m accused of being bad, but…who knows?" asked Kara.

"About Blabbermouth Barry? It's easier to list the ones who don't know," Iris said. "My boss, his boss, my brother, and a couple of villains."

"Get out! She's exaggerating." Barry shrugged, "Yes, the list of people who know me and who know is almost as long as the list of people who know me and don't know."

"Longer. _Much_ longer." Iris smiled. "Barry, I'm investigating the disposal of some black funds, and a name keeps coming up. Does the name 'Echidna' mean anything to you?"

"It's a marsupial, isn't it?"

"And a Greek myth," said Iris. "Symbolism alert: the myth is related to Argus, who killed Echidna. I know you’ve somehow dealt with Argus in the past. "

"I’ve never heard of Echidna, but it’s not like I have clearance. I'll ask around. "

"Let me know. Remember: Freedom of the press." She held up the coffee cups. "Gotta go. I'm theoretically getting coffee for my editor for a not-a-date."

"Good luck," said Barry.

After Iris was gone, Kara said, "You like her."

Barry sighed. "Does it still show?"

"I've spent a lot of time studying humans." She sipped her latte. "You told me to make a move. Did you?"

Barry nodded. "But...I wasn't fast enough."

"Irony alert." Kara reached over and squeezed his hand. "Hey--if I'm stuck here without powers, I'll date you."

* * *

The man in black was punching the bank vault door. Guards shot at him but he ignored it. The door tottered: its own weight tore it off the last bit of hinge and it fell on the man, who caught it and threw it to the floor.

Barry saw one of the ricocheting bullets heading for a guard; he pushed it aside so it missed the man. "Get out," he told them. "I'll take this."

The guards scrambled.

The man said, "The Flash? We were hoping you'd come. This will be a worthwhile test."

"I've seen those powers before," said Barry. "But they were with their original owner."

In Barry's ear, Cisco muttered, "Copycat? Ditto? Maybe Parasite."

Beside Cisco, Kara said, "We've got a Parasite. It's not him."

"I'll work on it."

The man cracked his knuckles. "I think I'm as fast as you are, and bulletproof besides, Flash. But I don't think I even have to move to destroy you."

Barry said, "Kara? Maybe you should have listed your powers for me."

"Flight, strength, bulletproof, super breath, uh..."

Beams lanced from the man's eyes and chased Barry as he dodged around the room.

"Laser eyes," yelped Barry.

"Heat vision, yeah," said Kara. "X-ray vision, super senses--"

Barry finished a circle around the roof and dodged back. The roof fell in on the man.

Amid the cloud of dust, the man was still standing there. Then he shook himself, looked at his wristwatch, and flew away.

"Try to follow him," said Cisco.

 

TBC


	2. Starr Power

**Summary for the Chapter:**

> The mystery of Kara's fate on Earth-Flash deepens.

Barry appeared in STAR Labs. "Lost him. I had to go up and down canyon walls, and he didn't." He looked around. "Where's Kara?"

Caitlin made a ta-da gesture. Kara entered the cortex and twirled.

"She's a little taller than I am, but we managed," said Caitlin.

"Kara--you look great."

"Great?" said Cisco. "Burritos are great. This is the stuff of sonnets."

Kara curtseyed. "Thank you."

"Why don’t you guys say stuff like that to me? It's my dress," asked Caitlin.

"Because...we think you’d be embarrassed," said Barry. "And it might make things awkward."

"Aww," said Caitlin. "That's sweet."

"Nice save, bro," said Cisco.

"Aaaand suddenly I don't buy it," said Caitlin.

"Caitlin--" said Barry.

Kara quickly said, "Any luck on the alien algorithm yet?"

"Right," said Cisco.  "I made a couple of simplifying assumptions, and I used Caitlin's measurements on Kara as a minimum threshold. Couldn’t use the STAR labs satellite but the earth-monitoring satellites measure the albedo of the earth. Low resolution because of aperture size, so I had to write an averaging algorithm--"

"Too long, didn't read version?" asked Kara.

"Yes. We have some kind of light-absorbing alien like Kara. Actually, we have multiples. We have a lot more metahumans than we thought."

"Good to know," said Barry. "I guess."

"I used Caitlin's measurements, and found one who is blonde and female and close to the right age. The figures aren’t the same as yours, presumably because different worlds. She's named Karen Starr here. Owns a software company."

"Instead of being evil, she absorbs light differently," said Kara. "I can live with that."

"Speaking of which," said Caitlin, "we should get you into a sunbath and see if it helps."

Kara sighed. "The government treats it as a cure-all for me, but it's not. And the last time I lost my powers, I needed an adrenaline burst too."

"Seriously?" asked Barry. "You lost your powers too? I thought it was just me."

"My cousin--" She caught Caitlin's look. "Anyway. I'd rather meet this Karen Starr than take a sunbath," said Kara.

"Here's Karen Starr's picture," said Cisco. A woman who was recognizably Kara appeared on the screen.

"Short hair!" said Kara. "How does she do that? I have to cut mine with heat vision."

"It might be disconcerting to meet a duplicate," said Caitlin. "I mean, a duplicate shows up. If you don't know about the multiverse..."

"Good point," said Barry.

"Well, I'd probably think it was a shape-changer, like a Durlan or a Martian."

"Your Martians are real?" asked Cisco. "Barry, when you drop Kara off home, I definitely want to go."

"Their earth is very cool," agreed Barry.

"This earth is a funhouse mirror," said Kara. "Everything's distorted."

"I think they all are," said Caitlin. "But Earth One Kara has a reason for not being public. We have to respect that."

"Cisco, tell me about the accident," said Barry.

Cisco started typing. "Background stuff… The Danvers, Eliza and Jeremiah. Both scientists. One daughter, Alex. They adopted a second girl, Kara. They don’t sound like evil doppelgangers."

"Jay didn't seem like an evil doppelganger," said Caitlin quietly.

"She's almost as good as you, Caitlin. Eliza has three doctorates."

"On my world, one of her theses was space warps. I read it. It was very good for Earth."

"I don't remember a thesis on space warps, and it's the kind of thing I'd know," said Cisco.

"Our government classified it later."

Cisco asked, "Ladies? Two years later, there's some kind of accident at the lab where Eliza works. I don't know what the whole family was doing there, but they were. Local Kara reported dead, everyone else died in the hospital over the next week."

"But why didn't I, I mean your Kara, try to help?" asked Kara.

"Maybe she did," said Caitlin gently. "Maybe that's what caused the accident."

"I did have sensory overload problems at the beginning. Maybe for her it was powers." Kara sat down. "If I had caused that kind of pain, maybe I'd want to go into hiding."

"I wish our in-house interdimensional refugees were here," said Cisco. Barry and Caitlin looked at him in surprise. "Really I was suggesting Jesse."

Barry cleared his throat. "Suppose Kara's right, and she went into hiding. Why?"

"Dying in the hospital sounds suspicious," said Caitlin. "Let's say the accident revealed her abilities and destroyed lots of stuff. The government steps in."

"The DEO," said Kara.

"Argus, on our world," said Barry. "They capture her, make everyone appear to be dead."

Cisco said, "So some people are probably dead, and the ones who are alive get to look like they're dead. This is serious X-Files stuff."

"Got that on our earth," said Kara.

"Did you get the crappy extension with Robert Patrick?"

"Cisco!" said Caitlin sharply. "So the government knows there are aliens and freaks out. It what? Starts making plans?"

"Hence Echidna."

Cisco said, "And when Blackout shows up in town—this is the government, we assume they know about Blackout—"

"Eiling knew lots of stuff," added Caitlin.

"—they work out how to steal powers."

"It holds together, in a tinfoil hat kind of way," said Barry.

"So does our Kara work with them or against them?" asked Caitlin.

"We'll have to ask her," said Barry.

"I'm going," said Kara.

"Sunbath," said Caitlin.

"I’ve thought of one other Debbie Downer thing," said Cisco. "These guys steal powers. What if they already got her powers?"

* * *

Cisco had rigged up a sunbath in Caitlin's medbay, concentrating on the frequencies that Kara absorbed. Before getting into it, Kara touched Caitlin on the shoulder.

"I'm sorry about the way the guys reacted. About the dress."

Caitlin smiled. "I'll live. It's not the first time a new and pretty girl has shown up." Caitlin helped Kara onto the sunbed. "Cisco just freaked over Bette Sans Souci, for instance. Though it is the first time my clothes have gotten a better response than I have."

"Ouch." She hugged Caitlin briefly.

"But I'm still not letting the girls out."

"Excuse me?"

"Quoting someone. Evil twin. Let's please change the topic. Close your eyes." Caitlin turned on the lights. "I've got six candidate molecules as your adrenaline. If I can identify it, we can synthesize it."

"Not have to put someone in danger? Great. How?"

"The stress tests earlier. I got a list of chemicals. But: Testing it will be dangerous. By definition."

"I'm willing."

"You are so like Barry. Just relax." She pulled over a stand with a computer monitor. "Now we can communicate with the others."

* * *

Karen Starr lived in a nice condo on a wealthy area on the outskirts of Keystone City. Barry changed and then panned around the scene with his phone camera. "Guys?"

Kara’s voice was filtered in his ear. "How does she afford this? I have to be superintendent just to afford my loft."

"Maybe it's a rental."

"I don't think I like her. Short hair _and_ a big home."

The woman who answered the door looked like Kara with one exception. Well, two exceptions. Three if you included the hair.

"CCPD," said Barry. He showed his identification. "We think you might have knowledge that relates to a case of ours. May I talk to you?"

* * *

"Nice house," commented Barry. It was decorated sparsely, as though she didn't need much.

"I run a software company. Have a seat."

Barry sat in an armchair. Karen perched near him. "We’re dealing with a group that we know as Echidna."

"Echidna? No, I’ve never heard of them. Mammal, isn't it?"

"We think they're connected to work that Eliza Danvers was doing."

There was the briefest of flickers and then, "I don't know her, either."

"There's some kind of connection to Stanhope College, in Midvale. You were in Midvale at one time, weren't you?"

"I moved around a lot. It is a college town, so you can probably find lots of people who were there."

"The thing is…we think your real name is Kara."

She laughed. She had a nice laugh, even though it was more restrained than the other Kara's.

"That is so not my real name."

Barry bravely soldiered on. "Really? Because we have some evidence that you're an alien."

"A person is asexual and they become an alien? I have had these hassles before."

"Like a space alien." Barry leaned forward. "Are you familiar with the theory of the multiverse?"

"Quantum mechanics? The Wheeler infinite worlds hypothesis?"

"No, the Fox-Gardner theory."

She stood up. "I don't care to be punked. I think you should leave."

* * *

"Well, that went well," said Barry at STAR Labs. "Kara, she’s probably not your doppelganger."

"Why?"

"I’m not an expert, but…" He put one hand in front of his chest and moved it out.

"How big?" Barry kept moving his hand. Kara’s eyes widened. "Stuffed?" Barry shook his head no. "Where did those come from?" She looked around. "A different lifestyle cannot explain those."

"Hormones in chicken?" said Caitlin. "Maybe that's different between universes."

"Earth hormones don't have the same effect."

"But lots of chemicals mimic hormones. Maybe one in this universe accidentally mimicked a Kryptonian hormone."

"She _can't_ be my doppelganger." Kara stopped. "Which means my duplicate is really dead. I'm trapped here."

Cisco’s alert buzzed. "Must be Tuesday in Central City." He checked the screen. "Looks like Kara’s powers are at work again, but with a different guy."

"Let me go with you," said Kara, but Barry was gone.

"I have an idea," said Cisco to Kara. "How much of Eliza's thesis do you recall?"

* * *

The man was toppling the clock tower by the square. Same uniform, different man.

Barry said, "If Kara thinks of anything that would have worked against her, she should tell us." He zoomed to yelling distance of the man.

"What’s the matter?" he called. "You don’t like flying?" _First thing, get him out of the city, away from innocents and guys who might have power-draining weapons._

The man rose into the air. "You want me to fly?" And suddenly the man was on him. Barry zipped to the other side of the square just before the punch would have landed.

"Barry?" It was Caitlin. "I just realized. He can’t hold all that power. That’s why the other guy flew off—he was hitting his time limit. This guy has a power budget too."

"So I just have to keep him busy?"

"And using his powers."

_Okay. Lightning first._

Barry ran circles around him, ducking the occasional out-thrust arm or leg, building the static charge. Then he threw it in a brilliant light-show.

The man slowly opened his eyes and looked at his unharmed hands. That made him laugh.

"Doesn't matter if it hurts him," Cisco said. "Just has to occupy him."

Barry nodded and started whipping up the air. The vortex got stronger and cars on the street started shifting, but the man just kept walking towards him. He ignored a bicycle that bounced off him. Barry phased through the punch.

The man waved his arm through Barry. "I can wait," he said.

"Supersonic punch?" asked Cisco.

Barry dashed off and then back, heading for the man, trying to remember everything that Eddie had taught him about punching, He was worried this was going to bounce off, but what else could he do?

He headed straight for the pseudo-alien, who stepped aside at the last minute and clotheslined him. Momentum carried Barry through a window and into an office, scattering the workers, who hadn’t had time to get away.

 _If no one dies first,_ he thought. He wasn’t sure he could speak yet.

The pseudo-alien was suddenly above him, and Barry rolled away from a vicious kick. The man almost lost his balance and hovered there for a moment. Barry got to his feet.

Aw, man. He was in a medical clinic of some kind. He'd seen defibrillator gurneys like those in hospitals.

He was on his feet and about to speed out--sick people didn't need this hassle--when he remembered what Kara had said about her early days with her powers.

_Perfect. If they have what I need..._

He zipped deeper into the clinic or complex, looking out for the right room. "Cisco? Kara says she can see X-rays. Is there an X-ray machine?"

"Imaging is down the hall and right."

The sign said Imaging and Barry dodged to let the other man's fist hit the wall. And go through. And destroy the drywall.

Barry dived through the hole, rolled, and came up at the X-ray machine. He opened the shutters as wide as they'd go (thank goodness this guy had to think about being fast) and shouted.

"Hey! Over here!"

The man started to turn, and Barry hit the switch.

There was a super-loud scream, and the man clutched his eyes, fell to his knees and pounded the floor. The tile shattered with the first blow and the floor buckled with the second one.  The man groped at the disappearing floor and Barry held his breath.

The man hovered there. He looked at Barry and smiled. He inhaled to blow at Barry--

\--And he started to fall. Barry raced across the crumbling tile floor and caught the man as he fell, then sped to STAR Labs.


	3. The Shape of the Problem

**Summary for the Chapter:**

> That's who Karen Starr is, all right.

Everyone was looking at the man in the pipeline cell. The man stood sullen and silent.

"He hasn’t said anything," said Cisco.

"Tattoo of an echidna on his biceps, though," added Caitlin.

Cisco shrugged. "Or a hedgehog. It’s not very good." Caitlin looked at him. "But it's probably an echidna."

"So that’s an actual link between the superpower thieves and the Argus-Echidna thing," said Barry."

"Information from our friends indicates we were mostly right about the origin of Echidna but wrong about the timing," said Cisco. "Echidna was created about the same time that our Kara must have shown up. It's hard to know what the relationships were because Argus wasn't called Argus then."

"So the pod arrives, they spot it, Echidna gets formed."

"But what do you do with a teenage girl?" asked Caitlin.

Barry knew the answer. "Foster parents."

"Maybe it was some family named Starr, maybe the Danvers."

Cisco said, "I kinda traded on Professor Stein's name a bit, and they did tell me that Eliza's doctoral thesis was removed from the library. It's before they were putting them on the Internet, so I don't have access to it."

Kara picked up a sheaf of papers. "This is what I remember of it."

"Which is most of it," said Cisco. "Now, her work is theoretical but there are some pretty clear engineering implementations."

"Can't you just open the gateway with your vibe powers?" asked Barry.

"That's between universes. We're talking inside the universe. Space warps. You have to make some pretty special materials to build one. We could have done it here, but Wells-Eobard told them to go suck it when he broke up with Eiling."

"And?"

"You said that Iris was tracking down some weird purchases. They lead to the Echidna lab, we reverse engineer the power stealing thing, and boom. We give Kara her powers back."

"We also take down Echidna," said Kara.

"A little more problematic, because they might be a government agency," said Caitlin.

"You can't charge into other people's universes and steal people's powers. It's just not right."

Barry nodded. "Agreed. I'll talk to Iris."

"Stress tests. I think I can narrow down the adrenaline duplicate," said Caitlin.

"I'd like to talk to this Karen Starr," said Kara.

"She's not your doppelganger," said Barry. "I don't think there's a point."

"True, but…she absorbs light."

"And if we need a metahuman, we'll get her. First, let's get you your powers back."

* * *

Caitlin was driving. The trip to Keystone City wasn't huge, but it was a couple of hours. Barry could have done it in a second, but he didn't think Kara should talk to Karen. Caitlin felt differently. She had talked to her own double.

To pass the time, Caitlin said, "Tell me about the last time you lost your powers."

"I just used up everything in one attack. My cousin Kal calls it a solar flare."

Caitlin laughed. "Is he related to Cisco?"

"Kal has a collection of Big Bang shirts, too. Of course, he _was_ raised on earth."

"Of course," agreed Caitlin.

"Sorry. You don't know any of this."

"Exactly."

"Anyway, this guy I like was helping me get used to being without powers, and I saw a robbery. So I put on the Supergirl outfit and went in and talked him down. Man, I was so scared."

"And that didn't bring back your powers?"

"No. It wasn't until I saw James fall down the elevator shaft—"

Caitlin swore in a way that she didn't usually allow herself. "If it didn't work then, it won't work now. We scared you. Maybe Kryptonians use different chemicals for self-fear and other-fear. Our tests are worthless." She hit the steering wheel with the palm of her hand.

Kara said, "Please, no."

Caitlin thought about it. If there were a different chemical messenger, Kara couldn't produce it here. There was no one on this earth that she loved.

Which meant that this trip wasn't actively harmful.

"All right."

Dusk gathered around them.

* * *

Cisco was looking at a list of parts and chemicals. He had scanned the list so he had it on a screen.

"That's all that Iris had, but she'll keep an eye out for more. Sorry I was late. Joe insisted I eat."

"Super. No pun intended." He drew dark lines through the relatively standard parts. "A kind of particle accelerator, but with a containment device that's different than ours."

"You can tell that from the parts?" Barry asked.

"They wouldn't need a space modulator otherwise. The closest one to here is…Mercury Labs."

"Dr. McGee will be so happy to see us. Caitlin better ask her." Barry looked around. "Where is Caitlin?"

"She took Kara out. Dinner, shopping, stuff like that."

"Is that a good idea?" Barry studied his friend. "You're not telling me something."

"No, I'm telling you everything."

"Cisco, I'm a metahuman. I can hit page back on that display so fast that you'll never get farther in the list."

"You'll tell Caitlin you threatened me?"

"Of course I will."

"Great. They went to Keystone City. To talk to Karen Starr."

* * *

Caitlin Snow was waiting for the door to open. Kara was out of sight. "Hi," Caitlin said to the woman.

Really, she looked a lot like an older version of Kara.

Caitlin stuck her foot in the doorway so Karen couldn't shut the door. "I'm Dr. Caitlin Snow. I have someone you should meet."

"I don't want to know," said Karen Starr. "Please leave."

"Just a few minutes of your time—"

" _Leave._ "

"You should meet—"

"Go. _Please._ "

Kara stepped forward so the light fell on her face. "Hi."

Karen looked at her and then at Caitlin. She sighed. "I guess you'd better come in." She held the door wide for them, then checked the hall for others. There were none.

In the kitchen, she reached into a drawer and pulled out two emergency candles and a paper book of matches. Karen said, "Before we talk, Dr. Snow, would you please light some candles?"

"Sure, but… Candles?"

Kara said, "Martians. She wants to see if I'm a green martian." Kara took the pack of matches, lit one, and used it to light two candles. Holding her hair safe, she put her face between the candle flames. "Is that good enough?"

Karen nodded. "Dr. Snow?"

Caitlin duplicated the procedure.

"And a bit of your hair." She handed Kara a pair of scissors.

"If we're martians, it will change back after we cut it off?" asked Caitlin.

"Yes. The shape-shifting doesn't survive through death. It has to be held mentally."

"Eliza built a space warp. Of course. She brought through a martian," said Kara.

"Almost," said Karen. "Two martians. The fight was brutal. People died. And somewhere out there is a white martian."

"But you're Kara?" Caitlin asked.

"People died," she repeated. "My name is J'onn J'onzz."


	4. The Trojan Horse

**Summary for the Chapter:**

> When a Martian meets a Martian coming through the rye....

Cisco was examining the list of parts from Iris. "Definitely a space warp thingie." He looked at Barry. "That's a technical term. But this other stuff I can't figure out. I need Caitlin, because it's clearly biological equipment."

"I'll phone her. See that she's okay. I don't trust this Karen Starr." He pulled out his cell. "Hey," he said into it when she answered. "Uh-huh. We'll see you then." He looked at Cisco. "They're driving her back here."

"Huh. Why doesn't she just fly the car back?"

"Surveillance?"

"Then they already know about us and there's no need for secrecy."

"No," said Barry. "I trust Caitlin and Kara. There's a reason they're driving."

"You could meet them, join them in the car."

"Caitlin has a small car."

"There's room for four," Cisco said. And Barry was gone. "Now I can read through the list without threats."

* * *

Barry got into the passenger seat because Karen and Kara were in the back. "Hey."

Caitlin yelped and swerved. Barry grabbed the wheel.

"Barry! I mean, Flash! I find that unnerving."

"Sorry." Barry twisted in the seat. "Hi. I'm the Flash."

"I've heard about you," Karen said. "You're part of Echidna, I take it?"

"No, I'm with…us."

"So that's at least three groups. Okay."

"Echidna and us and who else?"

"The white Martian. He's out there. If I use my powers, he'll sense it."

"But you've used your powers," said Kara.

"Just a bit. Just to grow up." Karen looked at Kara's chest. "I guessed wrong on the bust size."

"Why so…big?" Kara asked.

"Camouflage. Men don't look at my face."

Caitlin said, "They don't have to be big for men not to look at your face."

Karen made a face. "True. But I didn't know."

Barry asked, "Why Kara? Why not Eliza or Jeremiah?"

"I knew I was long-lived and I didn't know the culture. Being a child meant I could make mistakes and people would put it to childishness."

"How long-lived are you?" asked Caitlin.

"He's over three hundred," said Kara. "At least his other universe counterpart is."

"Yes," said Karen.

"Good," said Kara. "My cousin called J'onn, our J'onn, the most powerful being on the planet. With him on our side, we have a good chance."

Karen shook her head. "I'll give you information, but I won't do anything to attract the white Martian. That includes my powers."

"We could really use your help."

"Information only."

"What if we found the white Martian? Would you help then?"

"If we defeat the white Martian…of course. But I won't expose people to her."

"Her?" asked Caitlin.

"It's fluid," said Karen. "How could it be otherwise with shapeshifters?"

"Okay, that is not my J'onn," said Kara.

"When we're all together, we just need a plan, and I think I have one," said Barry.

He phased out of the car and vanished.

"I can do that," said Karen to no one in particular. "Have you checked if he's a Martian yet?"

* * *

Cisco was thinking of the best way to explain to Dr. McGee. He wished Caitlin were back to do this. Caitlin knew her way around Mercury Labs better. Caitlin knew Dr. McGee better. Caitlin was just better at this sort of stuff than he was. He should tell her sometime.

Finally he said to Dr. McGee, "Let me 'splain…no, there is too much, let me sum up."

" _Princess Bride_?" she asked.

"Very good." He clapped his hands together. "Okay. Multiverse is true, aliens among us is true, government conspiracy is somewhat true. Are you following me so far?"

"Yes, though I don't believe you for a moment. Do you have proof?"

"Yes. The problem is, we need your space modulator."

She put down her Styrofoam cup of tea. Cisco had noticed that she hadn't really sipped it anyway. "You'll forgive me if I'm not enthusiastic. My previous encounters with your team have almost always involved threats to my life, not to mention the loss of my tachyon enhancer."

"Answers. We'll also give you answers."

She pursed her lips. "That is tempting. May I watch the space modulator being used?"

"That I don't think I can do."

"Then my answer has to be no."

"But your questions—"

"Are not sufficient of themselves. I should also like to watch the space modulator being used. It increases the odds that I retrieve it."

Cisco sighed. "All right. You can help us use it. But it might be life-threatening."

Dr. Tina McGee smiled. "I expect nothing less from you lot."

* * *

Caitlin Snow was blushing. "I'm sorry I couldn't tell you, Dr. McGee."

"It is rather a lot to take in," said the older woman. "And I shall quiz you at length about Harrison at some later date."

"Now I can tell you," Caitlin said.

"Now, Mr. Flash, if you will tell us your plan?"

Barry was still on the fence about revealing himself to Dr. McGee. "It occurred to me that if Echidna had the white Martian's powers, then the interdimensional travel was pointless."

"I see you have never worked under an administrator who believed in power for power's sake," said Dr. McGee.

"I've been lucky," said Barry. "But if they had those powers on tap then they wouldn't need to test operatives against me. They could use each other." Dr. McGee nodded.

"And if they had shape-changing powers, then the two guys that, uh, that Flash fought would have had the same face," added Cisco.

"So what we're going to do is let them fulfil their mission by summoning the white Martian here. Between them and Karen and me, we can stop and trap the white Martian. Cisco has rigged up a containment device that Karen assures us will work." She wasn't letting them call her J'onn yet. "At that point, we move to phase 2 of our plan."

"I think it's always a good sign when there's a phase 2 instead of a plan B," said Caitlin.

"Our plan B usually involves punching," said Kara.

"Us too," admitted Cisco.

"And what, might I ask, is phase 2?" asked Dr. McGee.

"The Trojan Horse," said Caitlin.

* * *

"We're ready," said Cisco. "The containment device is ready."

Caitlin said, "I just thought of something."

"Yes?" asked Barry.

"We never checked to make sure that Karen is J'onn J'onnz. She might be the white Martian."

"That would be bad."

"And she claims she's a shape-shifter, so if she adopts the form of a green Martian, it proves nothing."

"Nah," said Barry. "It doesn't make sense. If she killed the green Martian, she could use Eliza's space warp to go home. You might as well claim that Dr. McGee is a white Martian."

They both turned to look at Dr. McGee. "Actually," said Cisco, "that would explain some stuff."

"You have survived some terrible things," said Caitlin slowly.

"And you're ideally situated to create space warps to get home," said Barry.

"That's preposterous," said Dr. McGee.

"Would you mind cutting off some hair for us?" Caitlin held out scissors.

"For God's sake," she said. "If I were the white Martian, how would I know where the green Martian is?" She made no move to take the scissors.

"Same way we did. Other people can hack satellites."

"Someone hacks ours all the time," said Cisco. "What?" he said to everyone else. "We compete."

"If there were a swap," said Caitlin, "it would have happened one of the times you sold things to Echidna."

"I don't know anything about Echidna," Dr. McGee said.

"You sold to Echidna," said Cisco. "Iris told us."

Dr. McGee finally took the scissors. "This is insane," she said, and leapt across the room at Karen.


	5. I'm Dreaming of a White Martian

**Summary for the Chapter:**

> So if Kara as a child and J'onn couldn't defeat the white Martian, how are Barry and J'onn going to do it?

**Notes for the Chapter:**

> Sorry for the delay--life got in the way.

Cisco Ramone was running. The breach room and the pipeline were not close, and they had expected to have time for this, but with the mad brawl in the breach room, they had bypassed plans B through I and were on plan J. Fortunately, every plan called for him to do exactly what he was doing.

"Hedgehog guy!" Cisco gasped. He really had to start training or something. "Alien! Not our plan! White Martian!" He stabbed the unlock mechanism.

"What?" said the man.

"Look, Echidna exists to fight aliens, and we've got one. We can use Supergirl's powers and anything else you've got."

"I need my phone!"

"Upstairs. Past aliens. Use mine." Cisco tossed him a phone. The man caught it and started to run. _Why was everyone in better shape?_ Cisco thought. "This way!" shouted Cisco as he went left instead of the man's right.

Yup, this was Plan J, all right: Freak out and get whatever help you could.

Good thing he'd bugged the phone.

* * *

Kara was hiding, and she hated it. This was unplanned and she had no powers. The white Martian was in its ugly glory, but Karen hadn't changed form. Kara remembered J'onn saying something about keeping one form for too long, so maybe J'onn was stuck in the Karen form. Or not: Things were copies here, but not exact copies.

If Kara had a power-draining gun like the bad guys—

There was some kind of speed-draining device. They'd used it on Barry, from what Cisco had said. Maybe that would…

The white Martian was saying something, but it sounded like the same kind of blah-blah rant that her white Martian had said.

"Get it away from people!" Caitlin cried.

"No," said Barry, creating a vortex with his arms. "It can look like anyone if it leaves the room. Keep it here."

_Great_ , thought Kara. There was something sharp and device-like on this desk—

She grabbed it. J'onn was bulletproof only sometimes. It was like a switch he turned on and off. So maybe this would penetrate the skin of the white Martian.

The room was taking a lot of damage. Karen-J'onn ripped up the desk that Kara was behind and threw it at the white Martian. Kara scrambled for another desk and ended up with Caitlin.

"Ideas?" Caitlin shouted over the noise.

"Just this." From her crouch, Kara leapt onto the desk and then jumped onto the white Martian's back. She jammed the device into the thing—

\--and couldn't find an on switch.

"How do you turn this on?" she cried, as the Martian began spinning to dislodge her.

"That's Cisco's Dr. Who sonic screwdriver. It doesn't go on."

Kara let go as she said a word that Alex had taught her. She dropped free just as the Martian backed into the wall. One big ugly foot landed on her hand and pain flashed up her arm.

Karen-J'onn flew into the thing's chest. The foot moved and Kara scrambled away on her knees and one hand.

"Let me see it," Caitlin said. She palpated the hand.

"Ow ow ow!"

"Nothing broken. Might be a sprain—Move!"

They scattered as the white Martian came down on the desk they were hiding behind. Karen-J'onn moved in for the kill…and the white Martian fell through the floor.

"Phasing?" asked Kara. "Caitlin, what's below here?"

"The breach room. The pipeline!"

Barry was already gone. Karen-J'onn became translucent and fell through the floor too.

Kara groaned and started running, with Caitlin close behind her. She let Caitlin pass. "I don't know the way!"

"Follow the noise," Caitlin said. "Where are those Echidna guys?"

* * *

Cisco Ramone was walking. Even through the thick walls of the particle accelerator building, he could hear some of the blows being exchanged, and he was in no hurry to see his tech being destroyed. (Well, his and Ronnie's and evil Dr. Wells' tech, to be honest, with a few things from Hartley.)

From the shuddering sounds of things, this fight was not going to last as long as it took the Echidna guys to get here, even with Kara's powers.

But they would get here, all powered up. He saw Caitlin and Kara run past, but he didn't follow them. He headed to the lab instead.

Best to be prepared when the ersatz Kryptonian ( _gah_ , he thought, e _ven a reactive gas like fluorine would have been better_ ) showed up.

* * *

Barry Allen was running in circles. He had to build up a tremendous charge for the lightning throw, and this area was designed as a static dampener: current should flow only where it was wanted, and the original plans hadn't specified a white Martian.

*Flash?* came Karen's voice and he stumbled as he realized it was only in his head.

"Keep fighting," he said. The charge was building but not fast enough. Pieces of electrical equipment flared to life then settled down because they needed alternating current.

*Telepathy,* Karen said. *I haven't used my powers for fear of being tracked by the white Martian.*

"Hold it."

*I can't. I am out of practice. You need to break the stalemate, though you're not as powerful as Kara was.*

"Thanks," Barry muttered.

The charge was nearly large enough. *Karen?* he thought. *At my signal, move out of the way.*

*Apo'kalyse will be free.*

* _Move!*_

Caitlin and Kara arrived to see the white Martian bathed in lightning.

Then the white Martian grabbed Karen-J'onn and started to pull. Karen-J'onn screamed.

"Fire!" Kara said. "Have we got anything with fire?"

Cisco's voice came over the intercom. "Spare heat gun. Locker six, Caitlin. "

"Where?" asked Kara.

"Why do you have a spare heat gun?" asked Caitlin as she pulled the door on the locker.

The white Martian dodged toward them, but Karen-J'onn punched through the floor and held it back, wrapping her legs around it so it couldn't move.

"Go ahead. Phase," she said. "I can do that too."

"Not. Opening. Your. Mind," groaned the thing as it tried to reach Caitlin. "Wise."

Caitlin stood up with the gun and turned, only to be hit by one of the white Martian's flailing arms. Kara sprinted for the heat gun as it clattered across the room: she scooped it up and cradled it until she reached the far corner.

"I can't hold on much more—"

Kara looked for a safety and a trigger, found them both, and pointed the gun at the white Martian as it surged toward her, free of Karen-J'onn's grasp.

Flame erupted and engulfed the white Martian, which screamed and screamed, much longer than it should have—and then Kara realized that the scream was in her mind.

The gun sputtered and fizzled, then stopped.

"What—" asked Kara.

"Do you think I would store it fully loaded? I'm not insane," came Cisco's voice.

"Did I—did I kill it?" Kara asked.

Karen cocked her head in a way that Kara never had. "No. In a month or two, it will be healed."

"By then it will be safely in the pipeline," said Caitlin.

"No. We must kill it now," said Karen. "While it is defenseless."

"No," said Kara.

"You cannot stop me," Karen said. A blast of air threw her against the wall.

"But together _we_ can," said Barry. "If you insist on fighting."

"Now we have to fight the green Martian?" asked Caitlin.

"No," said Cisco over the intercom. "Incoming. Echidna."


	6. The Echidna Attacks

**Summary for the Chapter:**

> They're trying to do everything right, including break up the enemies and get Kara her powers back...

"Get the white Martian into containment unit," said Barry. "Cisco?"

"I prepared cell twelve. I've got five hostiles total, three flying under their own power and two helicopters."

"Flying ones have Kara's powers. Ones in the helicopters might have the powers of anyone we've ever faced," said Barry. "What's the worst case?"

"Dude, we don't survive the worst case."

"Second-worst?"

"Barry, eighth-worst is the first one we survive."

* * *

Barry Allen was thinking _fast_.

_Why are they flying? Why not conserve budget in the helicopter? Helicopters are full, either with people or the power-giving gadget._

_No speedsters yet. Because of teamwork. They're going to come at us together._

_Got to separate them._

"Cisco, can you hack the helicopters, get them to land early?"

"They're protected against that. Maybe Felicity could but not me—"

Kara said, "J'onn can get them."

"Pardon?" said Karen.

"We're not going to let you kill the white Martian, but if you don't help, they will capture it and you. Maybe they'll subject you to study and vivisection. We're your best bet."

"If I kill it now, we can be away from here."

"If you kill it now, we'll never know where Dr. McGee is."

"The loss of one human does not matter against the loss of my planet. The white Martian must die."

"You're not the J'onn I know!" cried Kara.

Karen looked coolly at her. "That is true."

Barry said, "Cisco? How long?"

"Four minutes, five minutes, tops. They're doing a couple of hundred."

Kara cried out, "Didn't Jeremiah teach you _anything?_ "

Karen looked at her for what seemed an eternity. "I will disable the helicopters without killing anyone. Then I will try to return in time to help with the Kryptonians."

"I can help," said Barry.

"I can do this alone," said Karen. "Lock up the white Martian." She faded from sight.

"Invisibility is creepy," said Kara.

"Been there, done that," said Barry. She looked at him. "A rogue. There's no time." He smacked himself on the forehead. "Stupid! Should have had her take you. They probably have the power-granting device with them; you could get your own powers back."

"Run me there?"

"Two minutes," said Cisco.

"Ironically—no time." He grabbed the unconscious white Martian and dropped it in cell twelve. Then he locked up hedgehog guy, who had only just gotten outside. Barry hit locks and doors on the way out. They would only slow down the pseudo-Kryptonians, but they might buy some time.

Would they buy enough time for him to run Kara to the helicopters? Not by themselves, but--

"Cisco? Can you guys delay them while I take Kara to get her powers back?"

"From the reports of UFOs, I think Karen's delaying them now. If we evacuate the pipeline as if we were starting it, the vacuum will help strengthen the walls. The cells are airtight, so the prisoners will be okay."

"Do it."

He grabbed Kara. "Come on. I kinda miss the Maid of Steel."

"Me too, Scarlet Speedster. Run, Barry, run!"

* * *

Kara Danvers was burning. She was trying to smother the flames with her hands but a new fire appeared each time she put one out. They finally stopped in a forest, trees knocked down by the falling helicopters. Barry put her down.

Four contrails showed against the sky. "Karen's gone after the Kryptonians," said Barry.

"That leaves up with five to ten others. Let's get my powers back and even up the odds."

"One hundred per cent chance of punching," agreed Barry. "Let me just figure out which one has the machine." In two blinks, Kara was standing between the front of the machine and two unconscious guards in a crazily-tilted helicopter. The machine had slid against the wall, and looked like an elliptical machine without footrests.

 "I already set it for you," Barry said. "I read the manual."

"Great," said Kara. "And I hold these handles?"

"The Power Transfer switch is on the handles so it can be operated alone. When you're done, I'm going to pull the life support system."

"It has life support?"

"Cellular matrix from Blackout holds the powers. Both Caitlin and Cisco should see it."

The outside of the helicopter shook from a thud. One wall grew a fist-sized dent. "Just a sec," said Barry, and he was gone.

Kara took a deep breath and stepped up to the machine. She grabbed the handles.

* * *

Barry Allen was watching a fist. It was a metallic fist and it was heading for him, but for him it was like slow motion. Since his time in the Speed Force, he had been able to change his perception at will. If the blow connected with his skull, he might die, but he didn't intend for it to hit him.

He had no intention of being roadkill. Though they were in forest; there was no road near here. Karen-J'onn had brought the helicopters down in an isolated spot.

When the fist was about an inch away—plenty of time—Barry left, grabbed one of the Echidna agents, and put the man's chest right next to the fist. The five men were all wearing identical uniforms. There was no way of telling who had the powers he had seen on the device's selector list.

In normal time, the punch was very satisfying, and whatever the man's stolen powers were, they didn't work while he was unconscious, thrown against the body of the fallen helicopter.

"Missed," he called to the faux Girder. All Barry had to do in the meantime was keep putting bad guys in the way of faux Girder's fists. In a moment, Kara would be able to handle him.

From the nimbus of lighting, the next guy had Weather Wizard's powers. _Interesting._ The lightning didn't stop him from being punched by faux Girder, though.

The tactic stopped being useful then, because faux Girder realized what was happening and stood defensively, waiting to be attacked rather than attacking.

There was an anguished cry from the other helicopter.

* * *

Kara Danvers was a normal person. She had grabbed the handles, started the device, seen the lights, and… Nothing.

She hit the device in frustration, and the plastic shroud on the front shook. Nothing else.

Which meant that the problem was the same as when she had lost her powers before: they were there, in her body, but she needed them kick started. She needed someone she loved to be threatened.

She was in a different universe, away from her loved ones. She liked Barry and the others, but didn't love them.

She could feel tears leaking from her eyes.

Kara took a deep breath. _Time to try and help Barry. Somehow._

He appeared in a gust of wind. "And?"

"Nothing."

"Then we need to get back to STAR Labs. These guys will take a while to walk."

"Wait--smash the machine."

"You sure?"

"Do we want more pseudo Kryptonians?"

"Right." In a few moments, the machine was disassembled and the container of living pink goo was open and emptied onto the forest floor.

"Ready?" he asked her.

She nodded. The gesture made a tear roll down her face.

* * *

Barry Allen was panting. His hand hurt, but all of them were still up. Pseudo Girder was trying to get out of the enormous hole that Barry had dug, along with his identical twin, a pseudo Everyman; Pseudo Mist was up in a tree, where he had reformed. Kara clambered out of the other helicopter. He knew what that meant: if she had her powers back, she would fly.

"Barry?" Kara asked.

"Hold in." He created a vortex and aimed it up into the tree; the gaseous form of the pseudo Mist dispersed again.

Barry smiled between pants. "Thing is, I defeated them before. I know some of their weaknesses. These guys are smarter tactically, but still…" He held up his hand and tried to say, "Yay, me!" but he winced in pain and cradled his fist.

"Your hand!"

"I think I broke it against ersatz Girder. It'll heal."

"But not in time."

"I heal fast." He scooped her up while trying and failing to keep his wrist straight, and then took off.

* * *

Cisco Ramone was typing furiously. To make the sunbed as flexible as possible, he had set up the lights to produce computer-controlled frequencies. Now he was trying to reproduce the light of a red sun from memory. Something had disrupted communications in and out of STAR Labs—maybe it was because someone had rammed into the roof at over Mach 2, or maybe it had been a deliberate action. As far as the outside world was concerned, they were deaf, blind, and mute. Even the cellphones were dead, because the disruption had destroyed the phone repeater he had put in.

Caitlin was dragging equipment around the secret room. It was the only chamber that was both secret enough and small enough that the lights could blanket it.

"Got it!" Cisco announced, hoping the intercom system was working. "Heading over."

He was almost at the doorway when someone got punched to the floor in front of him. The man wore black and pulled himself off the floor, shaking off concrete and floor tiles. He looked at Cisco, who froze. Then the man took off.

"I could be a threat," muttered Cisco as he danced over the broken concrete. Although he could make a dimensional doorway, he couldn't make a pseudo alien go through it.

The man hadn't gone back through the ceiling. He had gone down the hall.

Toward the pipeline.

_Oh, great._

With Karen occupied and without Barry and Kara, they were defenseless, really. Unless he figured out how to do that thing he'd done once by accident, with Black Siren.

Of course, even that hadn't knocked Black Siren out, but with red sun light on the pseudo alien—

Call it plan M, since he was pretty sure they had gone through K and L.

He headed for Caitlin, to get her help.

* * *

Barry counted flying people. One was obviously Karen, two were Echidna, but where was the third? Unconscious, he hoped.

He zipped to the roof of the STAR Labs building and saw the hole. Ah. The other one was inside. Laser light—Kara had called it "heat vision"—lanced out of one to Karen-J'onn, who staggered under the force. Barry whipped up a vortex, hoping that the refractive properties of the moving air would disrupt the beam.

It did, and gave Karen-J'onn a chance to break free—but then Barry found himself in the air, with the arms of the second Echidna agent around him, and they were heading straight up. A fall from this height would kill a normal man.

"How's your power budget?" he asked the man. "Overdrawn yet?" He wrapped his arms around the man and started vibrating, not so fast that he would pass through the man. 

"Stop it!" the man said sharply, but Barry didn't stop. The man exerted himself to stay steady, exerted himself far more than just punching or flying, and Barry sped up just a bit.

"Haven't seen you before," Barry said conversationally, his voice altered by the vibration.

"You don't know what that could do!"

"Make you run out of power," said Barry. He changed frequencies then, passed _through_ the man, and clambered onto his back. "You can't look at me now, so heat vision's useless. Sure you want to be up this high?" He used his free hand to pummel the man on his back, each a blow that would have seriously hurt a normal man.

"Stop that!"

"I figure you don't have a huge amount of experience with the powers. I figure you don't know quite how long you can go. I figure I can wear you down if you can't get a grip on me."

"We'll see," the man said, and dove, picking up speed.

From the way the air thickened, Barry could tell they were approaching Mach 1. He wished he could ask Cisco how far he'd go into the ground at this speed, but he didn't want to jump off yet. It was a game of chicken. If he jumped off and created air vortices, he would slow down but be a sitting duck.

_ Play chicken or be a sitting duck. That's fowl, _ he thought absently. Patty would have appreciated that joke. 

The quality of the air changed again—they were slowing down. The ground was close, close, close.

The man had no more powers, or he wanted Barry to think he had no more powers, or—

_ Nuts. Sometimes you have to trust. _ "Hold on," Barry said, and maneuvered so the man could grab around his neck. He started whirling his hands, paddling the air to create vortices. They slowed, slowed, it wasn't going to be enough—

* * *

Kara Danvers was watching. She couldn't think of anything to do! Barry and the power thief had shot up into the air until they disappeared from sight, and then reappeared, a contrail behind them as they moved. Low to the ground, too low to the ground, the whirlwinds started, and selfishly, Kara hoped that she cared for Barry _enough_ , that this would bring her powers back, but her legs and belly felt like water as she watched them descend.

Then there was a green streak. Sometime during the fight, Karen had switched to J'onn's real appearance, and he was diving for Barry and the Echidna agent.

What was he going to do? He couldn't throw them up to counteract the falling; that would tear the Echidna agent off of Barry's back.

Kara started running for their impact point. They were moving too fast— 

J'onn cradled them both in his arms, putting himself between Barry and the ground, and slowed them, slowed them.

Kara saw that they were still moving too fast. She screamed, "J'onn!" when they hit the ground, buckling the pavement of the parking lot, creating a huge crater.

She floated over the concrete, tore slabs of rock and rebar from where they teetered and tossed them aside.

"J'onn! Barry!"

There they were, exposed to the sunlight. J'onn looked barely conscious.

"Hey, you got your powers back," Barry said to her.

"Is he okay?"

*I am just tired,* came the voice in her head. *I have not used my powers this much for a decade.*

"You're not…hurt, are you?"

*We toss children into ravines to teach them how to land. I will be fine.* 

"Then I'll be right back," said Kara. 

* * * 

Kara Danvers was flying through the damaged STAR Labs. The streak below her showed that Barry was coming too. The trail of destruction meant that she didn't have to let him go first; she just had to go through the holes. 

The third power thief was punching at the pipeline door. It was battered but still held. The dust clouds and the hissing sound meant he had breached the pipeline vacuum, and the door finally slid ajar. 

Caitlin and Cisco were lying there in the rubble; she saw Barry whisk one away.

Kara landed. "Now I know it's not a fraternity prank," she said, and landed a shot right on his spine. He slammed into the door, which teetered and finally came out of its tracks to fall onto the floor.

"And the best part is," she said, "You can take it. For a while." She didn't use heat vision. She could stop her fist when he wasn't invulnerable any more.

Besides, punching was much more satisfying.

The agent didn't try to say anything; he just shot forward, flying to the white Martian's cell. He was already standing in front of it when she rammed into him. "No!"

He took off, and she almost followed him—but X-ray vision showed her that it was a big loop, so she waited before the white Martian's cell.

The power thief suddenly appeared. She could see the flicker of Barry behind him.

"No," she repeated, and kicked him. He tumbled backward. Barry caught him and zipped him into her fist.

He fell down, unconscious.

Barry looked at her. "Hundred per cent chance of punching."

She started to laugh and have him a hug, then backed off when he said, "Ouch."

 

**Notes for the Chapter:**

> The extra bit wasn't really a chapter on its own, so I added it to this chapter. Now an epilogue, and we're fine.
> 
> When I started this, I thought maybe 3,000 words. Maybe. Thanks for sticking with me for this.


	7. Epilogue

**Summary for the Chapter:**

> Home is where they have to take.

"A going away present," said Barry. They stood in the breech room—Kara, Barry, J'onn-as-Karen, Cisco, and Caitlin.

The cakes had been eaten (Barry had one, Kara had one, and then they shared the leftovers from the third), and the toasts had been made. Iris and Joe had been there for a bit, but then both of them had to work. Joe had to cover for Barry anyway.

"You shouldn't have!" said Kara, and took the box from Barry. She opened it. "My costume!"

"I went over to Echidna's secret headquarters and found it."

"Thank you! I can't replace the cape. I would have hated to lose that!"

"Glad to hear that," said Cisco, and gave her another box. She opened it to see a second costume. "I had some ideas," he said. "Built-in radio, this time. And I changed the emblem just a bit so you could tell them apart."

"It's my family crest," Kara said, and Cisco looked hurt. "But the yellow background looks fine." Cisco smiled again.

"And I brought one, too," said Caitlin. Her box held a dress. "The right size."

"Well, I got you a present, too," said Kara. "With Barry's money." She handed Caitlin the present. "This version of the dress has not been through a fight. How's Dr. McGee holding up?"

"She says she's fine, but I suspect some traumatic amnesia," Caitlin said. "Being held prisoner by a malevolent off-worlder can cause stuff like that." She smiled, but there was some pain there. "As I well know."

"Barry told me." Kara shook her head slowly. "All earths are funhouse mirrors, aren't they?" 

"They are." The two women hugged.

"I guess this is it," said Kara, and hugged Barry. "Thank you." She turned to J'onn, who shifted into his green Martian form. "And I think I'll miss you most of all, Scarecrow."

"I am not a Scarecrow."

"I got the reference," said Cisco. "We'll explain to you afterward."

"It's time," said Kara.

"I don't get to see your earth," said Cisco. "But I saw Martians, so that was cool." He held up his hand, and a portal appeared.

"Think about your earth," said Barry. "Don't get distracted."

"Come visit. All of you. I think my J'onn would love to meet you, J'onn."

"I will…consider it," said J'onn. 

And she was gone.

* * *

Kara Danvers was eating pizza. "No, you were dead," she told her sister. "Jeremiah was dead." Winn and James looked at her, then at Alex.

"Weird," said James.

"And no us, huh?"

Kara shook her head.

"And Eliza?" said Alex.

Kara stopped chewing. "No one ever said. I hope their Echidna group didn't co-opt her."

"I'm sure she's fine. And it's another universe, anyway." Alex lifted her beer bottle in a toast. "To the Supergirl of two earths."

"Winn, you know what I'm going to say now."

They all chorused, "There's no place like home. "

**Author's Note:**

> When I started this, The Flash was still unfolding this season. Now the show has finished its season, and this is incompatible with that ending. It's hard to claim it happened in a brief period in the last episode of the season. So instead, I'll claim it's some kind of AU.
> 
> I'm trying hard for it to be like an episode of one of the TV series. There's probably too much dialog and not enough description.
> 
> Next time I'll try for a beta reader! Or an editor/continuity person. However, I'll go back and edit it to fix some details as I discover them.
> 
> Thanks for reading!


End file.
